1. Field to Which Invention Relates
The invention relates to a method for the consolidation of coal and/or rock in mining by injecting of a liquid adapted to solidify and comprising magnesium chloride solution with a specific gravity of more than 1.22, magnesium oxide and bentonite.
2. The Prior Art
Since the liquid for injection cannot, having regard to the pot life or setting time, be produced above ground and be brought in a ready condition to the position at which it is to be used, the three components, magnesium chloride solution, magnesium oxide and betonite are separately transported and are mixed only a short time before their use underground.
In this respect, however, various difficulties occur. 1 cubic meter of liquid for injection involves for example a total transport volume of 1.547 cubic meters for the three components. In this case the larger amount, for example 0.824 cubic meters, applies for the pulverulent solids magnesite and betonite, whose transport in rough conditions underground in paper bags or sacks is more difficult, particularly owing to the danger of damage, than the transport of dissolved magnesium chloride, which can be comparatively rationally carried out using tank trucks or pipelines in which the liquid is pumped. Furthermore, precise metering gives raise to problems underground.
Attempts to combine at least the betonite and the magnesium chloride solution above ground to form a single component which can then be stored and transported, have not led to success. The bentonite settles out too rapidly so that in the case of partial emptying, which cannot be avoided, of silos, intermediate containers and transport tanks the suspension is drawn off partly with an excessively low solid concentration and partly with a concentration which is too high. Stirring devices are not provided in the containers coming into question; furthermore they would be too expensive.